Read the passage. Summarize the central idea of the passage.

“Sustainability is the hot buzzword among scientists and environmentalists right now. But what, exactly, does it mean? Sustainability is the capacity of the earth’s natural systems to adapt and survive in changing environmental conditions. Earth has an extraordinary ability to maintain a healthy balance in its temperature, energy, and food chains. Although humans have only existed on earth for a fraction of the planet’s existence, there is increasing evidence that humans have seriously affected earth’s ecosystems in ways that may compromise its ability to sustain itself. For example, humans are using renewable resources, like trees, faster than the earth can replace them. If humans do not adopt sustainable practices, the damage may be irreversible. Sustainable practices ensure that businesses and individuals consume fewer resources and in a way that does not damage the earth’s ecosystems.”